Galvanometer.



J. L. ZANDER.

GALVANOMBTER.

APPLIGATIGN FILED 1111.30. 1912.

Patented June 2, 1914.

2 SHEETS-SHEET l.

@Horne 17| J. L. ZANDER.

GALVANOMETER.

APPLICATION FILED APR.30,1912.

190988? l m Patented June 2, 1914.

Z SHEETS-SHEET 2.

wenn L. emmenoie i mentir new" meent, mimo-ron; new

uring electric currents anni fire lijizirticuiorly moving reepectiveiy upon o. etre Z0 Operatesto return the sii pm? construction and 5,0 perspective View oi the core i3.

ein :ft it ifoeeietr t'tpecii'eetion ot' Lettere ltfetent.

.itpplcetion @led April 30,

MBL.' Seriali lite. (whle-E2.

PT@ all whom it may concern 4 Be it known. that i., Joint il. Siti/mono, e, citizen ot the` United Stati-ie, residing; V 'Neimrlnin the monty ot itssei envi titane 5 of New Jereey, here invented certe/in ne if and useful mpreveinente in Gfnivenor et of which the following Specification.

My invention relates tol 'improvements in gzrlvanometere which ere iicsigneti for nice-,fi-

edep'ted for nee :is electric tiiernioin las; mille volt metetej tiic object t; f `tion being to proiicle :in impro. ,c

'ment of coiie mounten?. upon iwi,

:finti .inciirteei` portion ot ii minijnetieeit com wimyeiiy the difference in the eiectro-nio ce cauees the positioning oi the coiie with re- 'lotion to the core While one oi? sind coil@` pi; to. nomini possiH the neceeeity tor nitmonieni ttor tionand diepeneee with springs or other meciienicii the purpose. i 'Ai further object is 'to provitle improve- 25 ments of this character which enziiile tlie einpioyment ot en orclinery dry ceii to energize the coils.

A. further object ie to provide :i 'Simple construction of parte which are readity :1o

i0 cessible, and which are not liable to get out of order, but which can be readily repaired in the event of injury.

With these and other objects in ifiew, the lintention consists in certain novel interes coinbinetione :ind ore rangements of parte, as will be incre fuily hereinafter' described and pointed out in the claims.v

in the accompanying drawing-re: Figure i i0 is a vertical longitudinal section oit" :i ngel-- vanometer embodying my invention, L. is a diagrammatic View iiluetrutinlfg the circuits, Fig. 3, is a plan View et the ilevice with the cover removed. Fig'. ft. is :i pion View of the iixeci magnet.v litiga iS e, View' in side elevation of the bracket F5, and the inechaniSm carrierl thereby. (i, perspective View illustrating' the Slmtt l2, and the coils carried thereby, Fig; L

My improved gzilviinoineter ie eiiiiporteti in a casing l preferably having e horizontal partition 2 and a 'reinovabie cover 5i, the latterproi/ided with :i elet 4t mongie i/inici.

tno dini:

-, initie connected np in electric cie in'iproyeinente ee Wilt be here- ;iefi. @n top oit the partition 1 ti 1e iociitefl, finti its peice concetti-ieniiy on their inner re prerei-zii'iiy connected by zi nreclret t? iS Secured by it enti i npliG w. Whit,

V or tno @wie civ :i igerticiil 'i1-ron is secured f' i* to the bracket 7 te outer surface spacco einen lont ile pole pieces ti, 'whereby forni. oir is tor-meti be ttieen the ottici core sind the pole pieces. ine core It@ is :termed of si strip ot' soit iron im'ing; one enel tiicreo" tepereti :is shown clear] y in Figa enti 75 incl the whole strip tient into cyiinciii'icnl t'orni. This is su rmigfifii ioe plie peice oit the nmgnet "term cross section opposite -one pole :indi that of diniinishingg- (fi-oei; eectiointimt ie tiie tapered portion, op? poeite 'the other pcie. By this construction :init erronjcnient the core becomes polarizeii eine to the induced megnetisnn and tile inzilgrnetie iieid. between the-pole pieces 6 is distort-eci :fine to the reluctance between the mijzpcnt ends of the Split cylindrical core, :intl tlie permeability oiE the opposite "eide ot the core. it will be understood that the tielrl between the Side oit' the core oi uni forni crotte section finti the adjacent pole 6 will ine more uniform than that between tile tapered portion and its adjacent pole 6 which veriee in Strength Witt; the taper. 'the inetnfl bracket ti connects the pole pieces on the sitio opposite the bar 7, :ind the latter is provided for the purpose ot connecting the pote pieceS' t3 when lthe device is being' ziefsenitiietl.

@n eimit 12 :irme it are iixed between their ende, and zit tlieir ende Support colis 15 and i8. The former l' shell terni the t current coil i iiecauee it directly connected to the tiel wy and operates to maintain tite coiie in norniei or nero position. This coil ie to enrro the portion of the core cizoee-eecton, it tends to return the same to that position, dispensing with the necessity for mechanical means of a'ny sort. The coil 16, which is arranged to surround the tapered portion of the core, I shall term the measuring coil because this coil by reason of the varying electro` motive force assumes a position on the inclined end of the core 13 in accordance with such electro-motive force. In other words,

while the air gap between the coil 15 and the core 13 is always the same, the tendency of this coil is to hold the sha'ft in a predeterlnined position which will be zero on the scale. The other coil 16, however, will tend to move on the core in accordance with the Huctuations. in the electro-motive force, and will therefore turn the shaft 12. This shaft 12 is provided with a pointer 17 which registers with a scale 1E. secured to a bracket 19 secured to the fixed magnet'. This pointer 17 is angular in cross section with its base flange cut away near its point so as to present a knife edge to the scale. An extension 20 is provided on the pointer, and this extension is'screw-threaded for the reception of a counterbalance weight 21, so that the pointer does not tend to ovcrbalance or exert undue friction on the shaft.

On one end of the casing 1, three binding posts V22, 23, and 24, are provided. Bind? ing'post 23 constitutes Athe positive pole and binding post 22 4the negative, while binding post 24 is a dead pole except when connected in circuit with what I term a bulb 25. This bulb 25 may be made in any way which will stand the temperatures and conditions to whichit is to be exposed and vary the resistance of its circuit according to its change of temperature. It may comprise a coil preferably of nickel Wire in a metal case as indicated in Fig. 1, said case merely acting as a. protecting cover for the coil, the coil being sensitive to changes of temperature. The bulb is illustrated merely to designate a part which is sensitive to changes of temperature. It is well known that varying temperatures cause variations in resistance, and this bulb is sensitive to these variations and 'is connected electrically with the-circuit, preferably by means of suitableV binding posts located on the casing. Vhennot desired, it is simply necessary to break the connection between the post 24 and the bulb so as to prevent wasting of the current. l p

A bar 26 is secured to bracket 8 and is provided at its ends with insulating blocks 27 and 2S. Block 27 is provided with two conductors 29, and these conductors are connected to collars 30 mounted upon insulated sleeves 31 fixed to shaft 12. These collars 30 are connected in circuit with coils 15 and 16 as seen most clearly in Fig. 5. An intermediate collar 32 is secured directly to shaft 12and is connected with a contact 33 on Loosen block By reason of this arrangement of .electric conductors, and the fact that they are of extremely fine gage wire, the tension or weight of the wires will have no appreciable effect upon the rotary position of the shaft, particularly as the angle of movement of the indicator is small. In other words, to connect Wires to the coil except by first connecting with the spindle or center of the are through which the coils move, there is bound to be some twisting or tension of the wires however small they may be.

By reference to the diagram shown in:

Fig. 9, it will be seen that at certain points in the circuit, resistance coils 34 are provided, the function of which will appear hereinafter.

From the battery 3a the current flows through conductor 43 to binding post 22, thence through conductor 42, resistance 34h,

conductor 4l and conductor 40 to the post 12 and coil 15, thence through the conductors 39 and 38, resistance and conductor 37 tobinding post 23, thence through con-v ductor 36 to the battery. .The bulb 25 is connect-ed to the circuit in the following manuerLA conductor 44 connects one end of the coil within the bulb with conductor 37 asl prevent sudden jumps and banging I provide a shunt 50 in the circuit to the coil 16 connected to the conductors 40 and 41 at 47 and to the conductor 46; and a shunt 49 in the circuit to the coil 15. The shunt 50 is provided with a resistance coil 34C and the shunt 49 with a resistance coil 34a. Coils 34 and 34b are used to calibrate the instrunient. The shunt 50 is only employed when the device is too sensitive, inorder that part of the current may pass through said shunt instead of through the coil 16, and the coil 34C is arranged in this shunt so that the shunt will not abnormally reduce the current in the coils 16. The coil in the circuit of the coil 15 balances the resistance of the coil in the bulb 25 which is in the circuit of the coil 16, and also insures the `passage of the current in the )ro ier* direction throiiUh the i section, a bar connecting said poles and arranged upon the side of said coreahaving the smallest cross section, a bracket connecting the poles upon the opposite side of said core from said bar, a rotary element supported by iid bracket and arranged concentrically within said core, a pair of coils carried by said rotary element and surrounding the said portions of said core respectively, both of said coils being adapted to be connected to a source of current supply and the coil surroundingthe portion of the core of variable cross section being adapted to be connected in circuit with a variable resistance and an indicator connected to said rotary element, substantially as described.

5. In a device of the class described, a perf manent horse-shoe magnet provided with oppositely disposed poles, an annular soi't iron core arrangedv in the air gap between said poles, the portion of said core opposite one of said poles being of uniform cross section and a portion of the core opposite 'the other pole being of variable cross section, a bar connecting said poles and arranged upon the side of said core having the smallest cross section, a bracket connecting the poles upon the opposite side of said core from said bar, a rotary element supported by' said bracket and. arranged concentrically Within said core, a pair of coils carried by said rotary element and surrounding the said portions of said core re- 

